Spectrophotometric Cp enzyme activity assays. (A) Fz assays. (B) pPD assays. For both panels, bars with different letters atop error bars are statistically different (P < .05) from each other. Data are expressed as means ± SD. For panel A, Ctrl, n = 12; FeD and FeDCuE, n = 11; FeDCuD and CuE, n = 8; and CuD, n = 7. For panel B, Ctrl and FeD, n = 7; CuD, n = 2; and FeDCuD, n = 4. Note that for Fz assay, we included additional samples derived from rats that were from a different study in which the dietary protocol and animal ages were identical.